Electrical conductor



March 31, 1931.

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i? f5 19 my j( M7125? @Y l ATTORNEY D. H. MURPHY ELECTRICAL CONDUCTORPatented Mar. 31, 1931 UNITED STATES PATENT OFFICE y DANIEL H. MURPHY,OF WEST' HARTFORD, CONNECTICUT, ASSIGNOR, 'BY MESNE AS- SIGNMENTS, TONATIONAL ELECTRIC PRODUCTS CORPORATION, OF NEW YORK, N. Y.,

A CORPORATION OF DELAWARE ELECTRICAL CONDUCTOR Application filed March15, 1928. Serial No. 261,944.

This invention relates to insulated electrical conductors, and moreparticularly to conductors having their outer jackets colored in a novelmanner to give them a distinctive Aappearance.

It is important that Wires and cables be identified or have adistinctive appearance to distinguish one type of wire or cable fromanother, and also for the purpose of identifying the polarity of wiresin an installation. lt has therefore been proposed heretofore to formthe protecting covering upon different conductors of different coloredstrands. For example, it is customary to form the covering upon one of apair of conductors of cotton yarn having the natural white color, andthe covering upon the other conductor of black or other colored yarn sothat the two conductors can be readily distinguished.

The desired color or distinctive appearance has been imparted to coveredconductors heretofore by forming the covering of dyed yarn, but thisincreases the cost of the insulated conductors since the effect of thedye upon the yarn is to make it tender, thus necessitating the use of ahigher grade of yarn at the st-art to make up for the reduction intensile strength due to the dyeing process.

In many constructions it is desirable to apply to the jacket of aninsulated conductor or cable a coating of a protecting compound whichwill completely conceal the original -color that may have been given thejacket, in

which case the use of dyed yarn obviously will not impart the desireddistinctive appearance to the finished product.

Having in mind the foregoing, the present Ainvention relates to a novelconstruction whereby any desired color is imparted to a non-metallicsheathed conductor or cable which has been treated with a protectivecompound.

In carrying out the present invention, a coating of coloring matter,such as any good grade of paint that will permanently adhere to theunderl ing surface, is applied to the conductor jac et which has beenpreviously treated with a protecting compound. Then over this coloringmatter is placed a transparent film of wax-like material which protectsthe coat of coloring matter without obscuring the color. The waxmaterial protects the coloring matter from dirt, moisture and thedeteriorating action of the atmosphere. It also prevents the color fromrubbing off and marking adjacent objects such as the wall or ceiling towhich the conductor may be secured. Furthermore, the wax film imparts aslick finish7 to the conductor which makes it clean to handle and easyto draw through conduits and openings during installation, and thedistinctive color imparted to the conductor by the coloring matter isclearly observable through the transparent film of wax.

Through the use of the present invention the insulated conductors may begiven any desired color at low cost, and a further sav ing is secured inthe manufacturing cost due to the fact that uncolored yarn may be usedin the construction of all conductor insulation,

thus permitting standardizations in the factory.

The various features of the invention will be best understood from thefollowing description when read in connection with the accompanyingdrawings, wherein:-

Fig. l is a perspective view of an insulated conductor embodying thefeatures of the present invention, the different coatings be ing shownon different portions thereof;

Fig. 2 is a perspective View of a cable provided with a pair ofdifferent colored insulated conductors; and

Fig. 3 is a longitudinal sectional View through mechanism for applying afilm of wax to the colored conductor.

The present invention may be employed to impart any desired color ordistinctive appearance to insulated Wires, cables and protecting tubing,and may be employed upon insulating jackets that are woven, braided,wrapped or otherwise constructed.

The insulated electrical conductor illustrated in the drawing is formedof a conductor wire 10 about which is provided a jacket 1l of rubber orother suitable material, and over the jacket 1l is provided a protectingcovering 12 which is shown as braided,

l but as above constructed.'

pointed out may be otherwise ta long period of timeso that it will notbecome hard'and brittle. While various sticky materials may 13, stearinpltch is peculiarly well adapted be used to lform the coating tinctivecolor imparted to the4 insulated conductor by the coatin 14 maybeclearly observed through the t in transparent film 15.

In the cable shown in Fig. 2 each of the insulated conductors and 21 issimilar to the colored-conductor-of Fig. 1` except that the conductor 20is colored dark while the conlductor 21 is given a lighter colorv inorder that their polarity ma be readily determined. `About the conuctors 20'and 21 is wound the insulating material 22, and theseconductors are enclosed in an outer jacket 23 for this purpose as it isfire-repellent to a high which if desired may be colored inaccorddegree, and retains its plastic, rubbery character over a longperiod of time, while it is suilficientlyadhesive to firmly adhere tothe surface to which it is applied.

After the stearin pitch or other protecting compound 13 has been driedor otherwise treated to render it dry and firm upon the conductorjacket, the color coating is applied. The coloring matter used may eordinary paint or pigment which will not become brittle when dry 'andcrack under the 'iiexing of the cable and it may be applied to thecovered conductor by passingthel conductor through a bath of thecoloring matter and then wiping off the excess coloring, but care shouldbe used in controlling the speed of the cable through the tank, and

also the thickness of the coloring fluid, to

" secure a satisfactory coatin which will not be too scant, or too thickan gobby.

After the coating 14 upon the insulated conductor has dried, there isapplied thereto,'in accordance with the present lnventlon,

a transparent film -15 of wax-like material. This film may be appliedVto the colored conductor by the mechanism shown in Fig. 3 of the drawingwherein the colored conductor 14 is shown as passing from a supply reel16 z into a tank 17 containing' the melted paraffin or other wax-'likematerial. The tank 17 maybe heated by the burners 18 and as theconductor 14 leaves the tank it passes U' which it is placed, and italso increases the life of the underlying coatings by protecting themfrom the atmosphere.v

' The wax coating 15 when applied in the form 'of a thin lm will notappreciablydecrease the flame retarding properties of the stearin pitch13, for, although the wax material is combustible, the very small amountof this material required ,to form the desired film will not besufficient to su port combust1on, and it will be understoo that thedisance with the present invention.

1. In the art of electrical insulation, a jacket for an velectricalconductor formed of interlocked strands of insulating material andhaving applied to the acket three distinct layers of coating materialplaced one over the other in an unmixed condition comprising, aiame-retarding coating of stearinv pitch applied over the interlockedstrands, a coating of paint applied over the layer of stearin pitch, anda transparent film of Wax applied over the paint so that the color ofthe paint may be seen through the protecting lilm of wax;

2. In the art of electrical insulation, a iiexible jacket for anelectrical conductor formed vof the jackets and so that the color of thesecond coating may be distinctly seen through said film.

3. In the art of electrical insulation, a cable formed of a plurality ofinsulated 'conductors each having a iiexible jacket of insulatingmaterial over which is applied. three distinct layers of coatingmaterial placed one over the other in an unmixed condition, andcomprising a iame-retal'ding coating of lstearin pitch applied over eachjacket, a different color coating of paint applied over each pitchcovered jacket to give each jacket a different color, a film oftransparent wax applied over each coating of paint in nonpenetratingrelation with the vunderlyin jacket and so that the color of the seconcoating upon each jacket may be distinctly seen through said film, andan outer jacket enclosing the differentcolored conductors. In testimonywhereof, I have signed my name to this specification.

DANIEL H. MURPHY.

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